ScienceNetwork Western Australia, Wednesday, 16 September 2015 article by Samille Mitchell
- Dieback becomes pathogenic as it mixes with other species
- South-west waterway ‘fishing’ reveals naturally occurring hybrid
- Discovery raises questions about how species came into contact
MURDOCH University scientists have discovered the first known natural occurrence of hybrids of the plant pathogen Phytophthora, commonly known as the dieback, which has ravaged south-west bushland and forests.
But the Centre of Phytophthora Science and Management (CPSM) research also shows that Phytophthora is not always the ‘baddy’ of the plant world that it is perceived to be.
Murdoch University Associate Professor Treena Burgess says Phytophthora species naturally occur in many areas throughout WA, and not all become damaging pathogens.
She says Phytophthora species tend to become more pathogenic the more they hybridise.
But she says the newly discovered natural hybrids come from relatively low-pathogenic parent species and therefore do not pose a big risk to native vegetation in the short-term.
She cites example of naturally occurring endemic species of Phytophthora in the northern sandplains which are believed to survive on plant roots with little impact.
However, if a seedling from its host plant sprouts nearby, the Phytophthora will kill it, thus ensuring wider spread growth for the host species.
“Everything that’s naturally occurring is here for a reason,” she says.
“Everything is interconnected—we just don’t see what’s going on underneath the earth.”
Before this discovery Phytophthora hybrids had only been known from mixing in nurseries, rather than from the natural environment.
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